Recently, a case-control study with a large sample size to investigate the influence of anticholinergic drugs on the patient's cognitive function in the future was published in British Medical Journal, a world famous scientific journal.
The BMJ: Anticholinergic drugs and risk of dementia: case-control study
In this study, some clusters of anticholinergic drugs were found to be associated with the later onset of dementia. A total of 14,453 patients developed dementia in 100,856 patients who were given anticholinergic drugs in the past, while 23,617 out of 233,847 people without anticholinergic drug prescription became dementia. The relative risk of dementia was calculated to 1.2.
Anticholinergic drugs are widely used in several fields of medicine. But their adverse effects are also concerned by many medical practitioners. Especially, the fact that they cause cognitive impairment to the patient is often focused. But there have been few studies to examine the longitudinal effect of anticholinergic drugs on the patients' cognitive function. This study suggests anticholinergic drugs are potentially harmful not only the term they were prescribed but also in the later life of the patients.
However, there are some arguments before accepting the outcome of this study, even though BMJ is a top journal of medical science.
As some researchers have suggested on the internet forum, there are potential confounders between prescription of anticholinergic drugs and the onset of dementia. Recently, some claim that depression in elder people is a prodromal syndrome of dementia. If it is true, the onset of dementia after treatment with antidepressants does not indicate that anticholinergic effects in the antidepressants are accountable for dementia.
It is also suggestive that only some clusters of anticholinergic drugs were associated with the onset of dementia: antidepressants, anti-Parkinson drugs, and urological drugs. Thus, gastrointestinal drugs are hardly proven to be guilt. Is it due to the magnitude of cholinergic affinity? Or, are there mediators in each patient with a specific disease? Further investigation is needed.
After all, this study has not proved the causal relationship between anticholinergic drugs and dementia. If you are suffering from some diseases, anticholinergic drugs are one of the choices, as far as it is appropriate.